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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f2a3d51ba7034055e9034b7af0d9fed6a5200f98ae8a38a54f176e987e24e70' 
  AND token = 'cGuSaHulgyhMpBHbXswQBpBMW6eLPJLma1M1TQIQYSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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