SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76b5ac76a973791f904ccc91cabe45ad9f9db92a160658c53c19a09b53ee949f' 
  AND token = 'uHNQA7zRgaLmoS7KVH3+E4eDvaJlvlhUsjnZDlPBaH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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