SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff0270c7be750bdfb6d0ff842fe40dfbedb70780c76e60ad4de4344475e361f3' 
  AND token = 'AziCQIzpwZ648UYNfxJ0y1MTpQNLaCn/DZtj1CFZ0N8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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