SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfc1848db45aacfa4ccd01b5facb3da6846675aee0eead1dc07091782f890682' 
  AND token = '3ZpctPpYmTpNtG56dfAQxUz+qedaazMsQt8KkkSKsng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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