SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e41a259fa30a244841eb0169f637d0c53c160ef45bf44f88b78b69fd2e4ed679' 
  AND token = 'k2hVaZ737sJPrF5GjMvfyV5K/e2ZgaSGzHIRLiTbTVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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