SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c41fbee756043be4462122f30b76ff8dd5aa8532aa17dbfc80fa9cf05861f267' 
  AND token = 'hgeSENyT99NLfwsle5GIXwMyDwMAYJ4A3jOcRUa1Qmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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