SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f4538fd9683e9940463d5f19927dfbcde6dd38cb430de1b45b2842a35d6a7c' 
  AND token = 'eUKCdBl3HVqQ9AI6QLcIWkZWhtjvXZXorHfn7gtzuZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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