SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3892c0107a6f040f7973721936278c8deadae6f7f264a4d9209017082b922972' 
  AND token = '13EMDk0ySNEJW+ZyC1/cQpI7x1suZ0OquWvnTgpdjG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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