SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7babbcbb934d2960848cbefa57474b8bb86456b221707d00b1736c518961e21' 
  AND token = 'bEC9HQpzORAZTCfwncVXxiGnFIZcuq3ro3YFCcpozI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}