SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47c61d67af088b21d7a52fdd7c307e8ab85ce61e5233df9f741a92b3147df2cd' 
  AND token = 'FXJJ3wj52sWcHrp0JDbHpKfT1CZQxVTGvFpSmJz6q5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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