SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17e15ea7c9ba550cb87207dffb00c70486fbaa3844fbafde54a4f7f505ec82db' 
  AND token = 'pyMhlFF3wbtLOvcu1RUs37gRn//TwS7Wx62Qx4X46Dw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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