SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2de6f2dc4141e8da660746c843996c41a555c96ecfe454d4acea29ff705318d8' 
  AND token = 'tos1PDLwXJMZz7P2XYz4+CVe0xGV3sDHXcVsXalFezc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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