SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4465546a3d2f6817e08ae53afe87aceabfe1b324b90afc5848b27e8f16dce3f5' 
  AND token = 'CwSURgoc4olDVviDxuLYcQvbyC1F6aQQs4MaAVHtO+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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