SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '874675193a61ed5f814aed090022f64d91a5077fa2f4a9f05636a449ffa0ac56' 
  AND token = 'llg+JrhekfNJGdFHtBZtBVy5SYR//1hEQfswC05nFQg=' 
  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"
    }
  }
}