SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da959851b4c60b9dd7fe553a0d18251cfbe230d123cb20b0b661fbfec99e7382' 
  AND token = 'ItCHX1P1CtH1eVg3+dKKLjV44IVwTZdPM/+IBZKeItI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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