SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0aa1e55dddbd9b12ec7137be027dde89923aa9067024a19320b7b7e5f00ab87c' 
  AND token = 'uKjObFmmwWzej+QVdAe429PfOtH7KGe8sqiUoPiTNwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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