SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50c1d39240827173c7b3f1e724bde584e4c7a207588cd8d13e548143f86a943e' 
  AND token = 'YPrnZ+mGHozBv2N0e6OFQdB0ZpgKH6W4+ANJMWaGXwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}