SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec24384001fd977fd3b5d7ef01f762d36d46cfff053d2d13aabe717d9851767a' 
  AND token = '1XkSuKMFN1OAODUQqqaKeJldCjfi2RMhSTifNvkQWsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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