SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42cdaeeee8a8d5c2d3ee2c6402edb835c881c31135d7163cd1ad05a8480ccc03' 
  AND token = 'TcWW2L3IwmYXwITDjm02EF/kK0HW0/dZXTtIUoMsfZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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