SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54d503fe00857063aedcd2c3db8d2d5fa587de3366f3fc5cf3af0372608eaebb' 
  AND token = '3xMHPLeoArGddFtJWH89dpImrgq/2cw2RZYMYlGyKX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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