SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1c6bd4f7d65fd9f8b58c9f44e847f54c5c1c3e315ddd724bc26e4dd3e630673' 
  AND token = '8GHwiDaLm6FmYo2UrcEDFXiWpZpfhjBKgytmrjOXsVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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