SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '076bb0abdd509d73ff25bd8e899397dc4635d3d4e0a59f9f42f43791dac239d5' 
  AND token = 'xq8B+CLtDXjAIRi5fwxOBXdXmObmQaiD85Wym6d0wAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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