SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c316609096915c40d71141cc34eadad8de201bad1c1f26fcf5bee2a5589819b5' 
  AND token = 'RQ+ER/luI3XBmUFZQ01fJehqHKVfxUv/ejNNojs7bTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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