SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '36ad9ec15514dc2d3d46ada62331d7c42599bd01348c00f0344871c38d02a4f2' 
  AND token = 'jjJQCZ9jdm9nWNaBHB0bz+5fHJ/BhMmcTMKa1uMID1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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