SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c000814b0ba38b62abd5a3c75653377015d6e3aa88751e3bc2ccea964b0f6785' 
  AND token = '7++RvHqoY25MsmVop/lz/L+qlOFj/dXPFLDZxVWxI+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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