SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eebc3fe24ac98f095e55adca88cbcdbd0654d2387a4101fdbc15770037838c2' 
  AND token = 'azWa4y9a8MldXPiTewlgPzc/gaTPU7+R/zKQPvnoAVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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