SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '604373030cc604261b37282108d2b5ae1510e85a534290229b016075c4128d80' 
  AND token = '40fnzCaA6+inicleeMhZbQRZaq1eazLCk8QUudXR1us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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