SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c17183b3b98c515cd141cd2d5dd923c16f3be1f72f25d241cb4fade729c691a' 
  AND token = '2lw/eWQTQg7FtP0/u+dajodMjUHASUUbJHtuZqXk/YI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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