SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f28409ca2a77ff35950d512360040ad98e4d6bf72950db30c138b35659e8582' 
  AND token = 'DnGIUfU1DO2IVPInf8PtLKcYX9oUL8EThLvPbT5iNqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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