SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b83dc68e0368ac7204f52751b238a7b554a9ddf179564c5f94b5c5ecb3fd4560' 
  AND token = 'T1S+otJqEMg/QEy5Z84XEXDd0uXrUjT0WkQpGtfg4tE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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