SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fec70431ff26e0e76ca175dc3cf403ec6c4ab3d74ab20cf67c566e521d8690c' 
  AND token = 'U+ccTX+EaS9kmVdVhB+dNiMQDVt96qAHpJu40IwJKXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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