SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd080c43bf65fbd0c716a010eba1f44a8360733a00a63cfb7a9cc6d3046ca3f18' 
  AND token = '1dySZoC2FlBQZQgSJXn3HkKtL0JvExlXS19ASKFzr7E=' 
  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"
    }
  }
}