SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78a54b312eccf94ec27c8dd8fd7d246571d6addf42070ea65e679fc95c873798' 
  AND token = 'c6aNbLY5h8GQn4zCsBSqhNnvUJj+Y7e62UZTvqMHjsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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