SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7953c4b3db4cf990b4fb8e0f3f6174b4d510a2c68280b95e292cb96860cef058' 
  AND token = '5W5aJbdC2UlZQlIRKKLhdChnUxGWXwjSPEaxVmYCmD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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