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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc5541f712d85db3165259c2e1b549b2e311f825310fed820147574de393c552' 
  AND token = 'qfzrqXQkbNR+Ny7DZ7JZ1Lzfz3ebV1LVEef2PfS5soA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}