SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5973b072734b07aab90beec57d1fe2334f7c9fbe37aca058cea493b42f008a72' 
  AND token = '6aMRv6dX8jPQsaSjstWFTXheW7lQEhtlRgknJwoLSGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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