SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc8b0e4d72eb6c941ac9c9dc767447b9c8dd8ee77a6a591ed188222dcd347415' 
  AND token = 'SYo88udh8ZZ6MKbLOUMyF9phJNsuQs/naGUYQkrPtwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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