SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c8c4b374454f4d183d331d027ab55f7871eedba9b98ccf65a82cfefdf640129' 
  AND token = 'yoOnP+xpzBB4xyuNna7csPkeWFE3ZboieoU3XiXf1sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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