SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5db5d143dbb20cd099cd91865193b982e6ff1f61edd196d1693e8d3eb5e6eb4' 
  AND token = '9xdLPkfooSutUiitAGNUipNAGyc5ek5ztt4IKrPcLXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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