SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '518307af9c321f8fd763724e23ceedabfb5d3b34647e6fbe10f68e5a89b656d5' 
  AND token = '4P6Ie8szTlJm5t9hwBmuMYRcZJWYCunf+BpOoptWD1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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