SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2b40bb73bc367b7f33000e0395be0f5ce8d8e22bc95ce146b6411f529b3813c' 
  AND token = '+gFSnwew73pJVI8cdKjM/SpbdqJQlWRjOZFYbHWWlP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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