SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c738249878375d50771979ef81ddd9e1a099927a9968a3fd10a7b3484e516818' 
  AND token = 'YmUCDYA08h1Lej5yXWmCbQXcftRAdAgAI78o1HkVaeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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