SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd063042420c4095a3a435d72176d6e17270388a4fe764a42f2609a96aec4d0a7' 
  AND token = 'Sx6xKQv/B4WTacKSZi97yxvMT3TWyiy23BdusuHoXog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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