SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f708643fb1a874e56b4a2be0dcdbe86e9542695433ba38c584da51be3f874ee8' 
  AND token = 'dAVGqqIBxfcwWCFbS9QEb6Prk3YDaWa3/WHzbgqk/ss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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