SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f3733987ab073093c83fe45a1ab38d90ed1a1f76f9136d280707cb1a78250321' 
  AND token = 'EqAbOI9PrrDizlGgUh5e47Iaz3nM1nRUmVEGYHyFyUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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