SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c69c03d3c483436061adb35e77552214892e429c7f6d27b453d8d9be2098d81f' 
  AND token = 'fDiJjmv8qtIylGQ9A99t/UTqBLihsnLhJX2h/e4Rudk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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