SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '076c80e7dd272fdbd86a899d180d6582558832d10a98ae43a56b302f43bcf39d' 
  AND token = '1hiuGr8P0sg0nXkaIJUmblAkr+28GGozzyMRrX4BzWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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