SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed7984f820ad20d0ff0e45299713f7295fde7855634973e20b221db03c81cf67' 
  AND token = 'vRkaIvo4VqT4xPY2AiQ3Iv86GvG7uMYbb+T4WZUMna0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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