SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb856a46c381613124850b0ab8cc9cdc63e6708a50c726f507414bd257308f15' 
  AND token = 'ddzHwwLfI0LTq3jxqWV2nk/lRB9KYTxV816vh4W8i+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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