SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '71a047a312bfeb573b6767303add1329f3d44f41d0069a8dd6fce9ce23b0287b' 
  AND token = 'Xul71WDYkKXvJFlCWMsj/PWKdbSP/INV08Cpw/Komx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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