SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85ccf00ad517832188644d4a7aaaeeefc2aa41fad44841fdea9f8efa53405101' 
  AND token = '2dL8FChqjcUqeEKz6rwtcgxuxmR06n8/nPnFKMJpLHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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