SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a275f62f09c6f0ff1b65397de4b10338b47b8ff0b5e6cb07de604b2c1053d1a' 
  AND token = 'gCQpblGIkSXWMf0hT9Zib8Jr084YU/avkzRPIZA3MUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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