SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8720c61dd129f68c0c45c2a09395586938dcdbccc180336e567b8bbadc4daba7' 
  AND token = '/DOKDoI8gvJQZdwaKc8xXbpyJB1qMnVyisUxe1vqiQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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