SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19d37ad341eed1a946d742a9626ccc77e70b5cf904d246662e647716d359ffb2' 
  AND token = 'QTaay6XiYPEtTfkXW4wzieAVlXqY3GVvlUjdoIxlkTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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