SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe936db0041b2ce22ae4bf8790f0c87fa76c67a1858f132f85da8b4b40c346f' 
  AND token = 'VEh/+E74tqXkbbIKtATzJcYY8OluSZw3dCYP5jKJoio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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