SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fcea44063a551b489e32afa4633e979addc278cc36252f1ad140e80fb0d435b' 
  AND token = 'aAbT4eHZOd3pvx4MWiIqaDjrBtDLDzhINJPCZQ4Zg4o=' 
  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"
    }
  }
}