SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f92487c6eb69dd554ca9c626a2f54340c6c48480c78d89a31387b498e668096d' 
  AND token = 'nRv+Fc9zDWq+wUO1Y5u9ShAp7jzKcLNDHVZhCtGxMNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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