SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8983d61823c21988831b7077f83c0fc43a8c20c4618903474340620f7f258b5a' 
  AND token = 'DYMJ/ayH+duBQVHpKdwnrtv/PBCu25EKkUunGJebCRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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