SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a3b351668200f7548c5d50a3b53760583a43c28f4c79fab4574e8bcb6d4b040' 
  AND token = 'hZxyjbOnR/JKkFppSh8/Vp5GK/3BXDjT/HeawI2FmWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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