SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a0817ff08f3a6d9129b7fe3057cc5441218d8ac76d8f061c086338c0cc7408c' 
  AND token = 'rutRuSyqFhnbSpiJqYtb0qQTGIyacRG63gkAIAGkfKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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