SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3836230c445e7beb836eacd2ca4b7c288720d421105aeb8f9803d056e5957940' 
  AND token = 'GrRfLiEbqOR06/FHs9OmHXeZCvY6g9tZt2nGTy9ONx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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