SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36ec399c495d48e6fb25a4ae3a37f8e289537f415dd32830b1923739f9cfd14f' 
  AND token = 'usEodarMchO0fDFnKBZzSHWPvBnXs2TIwH+V6qXuQFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}