SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbef5f06b7250b7c026562275a433885e9b495992e956e07100196e3e93440a5' 
  AND token = 'BNUBo7D1rWzo6MrpOhz3PTjnfNh9WFTRCJGlzhBASgI=' 
  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"
    }
  }
}