SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ef47a5f0ceff294183606c2e584c4af6a37eb9378f7b883b1481368133606c3' 
  AND token = 'LnTzqNf3LyVTWUJ9WiHYWewJibesuiwDWlynousffE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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