SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f391b0d0a15d7a63f953f1f706e910796b5dd0fe9fede6d960d1fe4e0bed07f' 
  AND token = 'xQKmcx8Vd1lyIpbKjQpZVfdb6CPPO/RcYVE91/zSWAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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