SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '39843d248e606cc8f59922f314f9db0db0e9d47efd1d7b0ae50a24528ff049c5' 
  AND token = 'arMT9Vvh11kgPDm2S8A8CcjvB3mW+TuMFHF3dfVTt8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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