SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c245c8827c96e9f2ab8b7f83c120d532487429437a3d7848888a320532138099' 
  AND token = 'DZNsprGSHhNfzjTvwWaZK4hbP7RiN0thxIuEmdg0mdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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