SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a928a5dc745ec0d4d4c5dee1b875f79d108266ab93644cc6b402a4308598bc99' 
  AND token = 'xfREZi7ZFvV/x1Z6jtHGnVj+gIrDbZXd0vooGzx31Ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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