SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0af712a9053bc9afa4e67bc16e337be9ced35b7df5bb30817ed2a59ee742ac93' 
  AND token = 'sWlJ9FKj7ePQQ7R/fsjvyuypOjzERkgGVvCvIEXl3TE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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