SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77e177b4dcf489d263026924d0a03c6d56994288ec504d751fa00209e21c8a4c' 
  AND token = 'HAwbKt8+r8MWumqLZ4ZyZwIdRB6FoUIXKs3bRratVaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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