SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d47a3255d640f663b5c8795f70111a1ddf5405a07d6b579c7e7997fd3a8bde6' 
  AND token = 'hLD0iSeWUUhmGUs7Fo6dwYyaehtQqrjv4dPrtapngVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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