SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de3b2e7915616d975b5a8125c8d36631dfd8eb678ed0f4783636a84f95e7723e' 
  AND token = 'URdcPakKoGjFvqrIm5Bz/LOhar9Pp5FXbG94zKVpumU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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