SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '414d1123c3975948cdf394fff8f6024dca1d89a1f81f9b270ff7c29a390c3d7e' 
  AND token = 'QRvua9eIg4cGNHnSCk7zMqt+yk2I8y+EWJC+5NktDBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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