SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '745be0256565be9fe5da91b2232eb58a43472dd6a67295c56b4a746073eeae2b' 
  AND token = 'VYE7SYZWWiOb+RALSqzH1Q7tWzFhvRHlDnUiWpywYK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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