SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '033169e959de1c6f793726dd1a41dd1bc970f278f6fc9f28223ba147a253920b' 
  AND token = '4pV2MTnKLiVZKng+BW6d0cYtFODI3yeYgIFxBGzIW+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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