SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dee3709053002e4a304181f1852697f3e89a83752dc030f55adb1e8f1bc7900' 
  AND token = 'eP3rky4+eG02YKLRB1XhQohPgY8vSII/2xkqFaUztoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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