SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc47309f0af350fc2a7749e24dc532c79886ac534966290cd3395535e93add93' 
  AND token = 'KqaDtEvkT4PJ8XsxULqaKN1e8jmLfzXaCK3oNnC09rE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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