SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e392e7db31b58972346adff4755ed8a5d570ff9a961657c402c9337427ece93' 
  AND token = 'M/Wsql+0YilIMoZvAjoHlq8wPuq94SFrHNcS8zLE1G8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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