SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '241dc22032687073c253a73b2ff8322a8340c6ea17de2695848df6fb44414b7a' 
  AND token = 'kb+edWKuLPjdBmPPq+GUzgENGUchQjfPEZAiIzcguRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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