SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b934a507584c819e9d79e0928ac75ce53cb8199ed40d003726cb6f806a21d9d' 
  AND token = 'vLmQiazgppsH+vKBxiIvfQ33Jnl6UBrDWEKuS0fnsl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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