SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fa14d033c628f61de858e95373a99bfd20a068bbf6ea182b74c225db9e4b42a' 
  AND token = '6/NIJ/yRCXj84VNlFqgjQzwBH2SaMorGjriKHGQw2yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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