SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd72fb6f809e50d53d2269b831b1dff56a92b2a716606c184352f5c2517b8f67' 
  AND token = '8IBYCk3ujQN+v/2SwBvd/zBb2LAikPBggzntAqI4wAQ=' 
  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"
    }
  }
}