SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cb4454a96b202f64835c8ea7b63d03235dd6883a5e2c0b5782ced0f010488d2' 
  AND token = '8Y8G6FWexBZ6vm8soZfJu5qHDWt3+oWvBLOlXLL9Wjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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