SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8df7b387e7505b359ed0603635fabb827ddd215a658209b1b2c28c43b4b05eef' 
  AND token = 'LkvUtS70op7ezGjwh5mjGz2HwIMzEDkiEZIGm9G9mvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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