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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9435b276eb5d0f4e0704a4d7b16328dd9f235570351bb5ffeeeca31670ec290' 
  AND token = 'XCkpuiqFrgNzgw41eon+NL6aBiitq3tzFWi3OaeE6+o=' 
  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"
    }
  }
}