SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cb9b2b052c436c8fbcda7292fcbcbbb4090dea7cadfee5dd9f756412c3ad689' 
  AND token = '8kmW0IaElOR22RBWkYavYsh1E1EtYUF0gIOQnohODls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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