SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4ae4f4929e3b47c11c9387241e5d0e27562905866d11732a632fc4417965d97' 
  AND token = 'wr9Z+9EcdVG0TxZi4+RBlbKhhy74vsHZizDTePgUmFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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