SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '854efb92dfc1405aa5a1f1517e8aa096dae828a491d3c2bfa49216618ae5c90f' 
  AND token = 'DLHHEhJIoj2tKzTXQknPOvWiLuomrXzDAa6hfNNbp44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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