SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b03dda145b69cc4fe43f612d973db0905865a719de8fde5242eaf7203d7d620d' 
  AND token = '9mugZ/hEpqQnUuLUuRPraElPLIIUd6IP9K5actIhTaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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