SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d3db47345f4bd0307c144232c4ad3db47666af6ffa26f5503438ffd64f48b75' 
  AND token = 'I9Jaji2wzBsIeZnKP7YnUsUcv8bCnldImn3uY8o4od4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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