SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd773d839a8e03e01fedf81bb2a2447ba9c67ba9c2397642043ad678504d76587' 
  AND token = 'BLhw+o4MrkLsFYk456ucCf8WSyWhpaVBFMUxy/QJKwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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