SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cb7e9170b36ba1a2d3036ea45a8afd0e2ab8c777c7c02c34def656bfd9f7e3c' 
  AND token = 'g3Kdp8fzh44D8nmkINPYLy4vCcunSvC/z5T/RZ+2HJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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