SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a2d099dd9653e8d5bcc198aa46e2c76f954fd31f9f5f9f16976d4e89928de71' 
  AND token = 'UiD3cHqaZL/dzbMVpq1B4Y+oArYRP5wHbLn3VW6IqlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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