SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0a3305015fad985e201f7fb7cee8d13e86047ae5fbf6dcd518341cff2affc66' 
  AND token = 'wJwzQZq9/qrExH80ZH1OjBTT67dgpRLIVqworogBBkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}