SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9414c421a3eb5b748138d9d934133ef60a4336f44fec7837f2147ddaa05eba48' 
  AND token = '5K8umhJvBtxLHj1cmQgn86/atBTlllVL3bFsV85pGTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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