SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5707c8afa4d1a8ed2ab24fc750c2905f7289942bf15d0e3a68273569286e44ea' 
  AND token = 'ETCNU2pgYAk/c5VXFWwcBYpqtwj1qSo6uB3Whs4V0Z4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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