SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76df6b7e128879e975981f3000857884cc5779b5d89dc066de3b59dde2d15733' 
  AND token = '5TC+jayRw41L2MxFNHHVLYxEGy/4dPCXiyunQSpLFgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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