SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f8b0242270a846dc1d1d1cf81c5d8eab8d110609842f641c3d3d31982c10134' 
  AND token = 'p9cZiPs85n3EAnKKsASdn8iy9qdW8Wv2dvRIz5pCjfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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