SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a2cbe34f068f0f288095748f771366f6352108c13f23255489e2757d8ad38cec' 
  AND token = 'QV+L3HTBYPCluV3tkPTeStgu0qHq0VmJVyuWscKlc/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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