SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0f9de185f7112ce8e8743cecbdd334c627ec06bbe2790f5e642580143add93d' 
  AND token = '25cHdcPB18oY0nQgZ/1ZanJVGK97rf7+RRBLipQrR6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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