SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15b0a29a9ce86f17050085187689152a788507b7d30f995655d28fcf6f972ea9' 
  AND token = 'yWzXa27gi0Mg2dvc53YOf/7NnEM9uGShK1Fosz9VloA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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