SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63c6e60cd52227f8a3931afff758558cd34371a743b5f2a05c1486c3c5b48896' 
  AND token = 'F4K1+QPe9+OaSDsMQXXD1//J24R0DOwRBi+WvGpOVRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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