SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb3df091d7826b5d6d2b3405bdd0b4646eb916efc74a140475ed33bbf8a1eef4' 
  AND token = 'vk0AvUxIMF5uxWD66oHOQQ2YVq3XckP58j3VF3A8FGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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