SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c90f7a166c24589d0622f4d7e53e5e33b5522c2d5ff97d260f7c2cc632117767' 
  AND token = 'H50XUJUuRImKNgNmAZJzbtdnRUGYxWgeZZnqHl8x0w4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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