SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a5384c7b48fe6ed167bf79b2e443c7b10fad34526628edb2bd99e00627f0d86' 
  AND token = '5VB6CVHZ9TNQHnbLeTuXqh7+WWcwOb2MhDJIAwjgEHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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