SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83c112acad8ea077ca83c55adea6010e373b438faef4dc248cd1ce173607760d' 
  AND token = 'Oqe7hCtbtyz2DAahKxCXbWN44evKtViQr/4cAK9TECk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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