SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '890e203125b164710d0ad46e5671ee9361c5d18fe66901f5f1b00c1162afd277' 
  AND token = 'LTtlD/5BB1v2dIJyNrUVIHb+fVVDV+uSRr2LPKblnD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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