SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b97bf1a4cc664503575512f397e35be8c1e1e028411b82c196abcd60d993f479' 
  AND token = 'v44eHHbZlB5gvrxJ7smo9ae85Lo+jALpmSUBUTDsdqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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