SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a9368d429568f8f7edd8a182d49411f599f615924f86876b018fa2c97f641cf' 
  AND token = 'KZ5XDqjiXaZnuZjDhhLnirTr2T9lLGWhPihGc1APRzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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