SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42cfe687438368b11ea83933a32aa0c32d248539c3c8adef338ef8d8b15982c7' 
  AND token = 'p8nZaSS0LOxQ/3acVR7YQJQFX5wdarnthouQds8cAtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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