SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f98cef97573846aaa232c21cbd3be2d827e3071351273f34a72c07712382d88' 
  AND token = 'D530iGzt8jtAaodobcSnSTTk2SENqe7qa3ajRRF8rh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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