SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21454c31fa5635b071f7aab83875c3be4604084507533a685f2ddd7ca5ab81f3' 
  AND token = 'Pl4Pc45ghEpo4a2OGcHq3zrKdshUU5y9ORgEjiGffs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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