SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b2de84b52a03a8448fbd90e4227632da792e7d1257875154bd8b3faa5f6a9e1' 
  AND token = '+33CAaQZdjmGXLHnLpguYohcvxmXZY2SKXu0S0/PleI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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