SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd3fc5621dfab114a3cb8731a297d7a587f338831f85c3a4783d9557290dc198' 
  AND token = 'SdKdMbGElHKhsX7x+FAxhIHKpuHkowBJzTZGyNQDFyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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