SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2389b768d7ba44f20a7ee84017dff86a186a4a57fe366cf8e7c62e942695460' 
  AND token = 'l0N3k1xxTqUkhcQZhHlQYg6XoGfB/Bw+fWnFo7Bsmss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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