SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb0f90f42068f2d6cc915a87d0bbd831d50679128b813133f9f9a58d17f7325b' 
  AND token = 'yHfYkfHOq8bVgyfBkvHqp3YMRJxuaoIARcncnzD07BU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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