SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a4119c8323a5733bb49e696378d0091dc53a20abbb479de0df5735d20752bc7' 
  AND token = 'hMq+6RheyIuFpSWN7jYTEAvce3ad0VRhkVYhcIMPXzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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