SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '020fac798c5bc826e70e50d550670fe59beb4c9d2ffd9c46f5d6aadc1ff356b6' 
  AND token = 'M3ggvt/0VvPQnKRpvaQuAxLJdZLgCBnRRht+v4jPbIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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