SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17dc41fe6999cb52f5ab05bd0f388fa424204e8b65e980a9868b269c9ef7f19a' 
  AND token = 'CyyEw74NUTZBEyukxHEn71/PVuFZaI4BBpYcRPjD+NM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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