SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c63f6612f864b21316a943f11848a5f1c3ef65519b6e43a099176edf107f938' 
  AND token = 'RA9QLEUh6nYpkMeWhOMmwFxuefoYAB8QYNpWfuNVT/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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