SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f775f724f684d4eda5ceb64c47482c4dd2a383ecfefd101fe67f3df4eeaff0fa' 
  AND token = 'JIsidB86NtQXjFAe0yBmdqIBKqH9JUTMqepXjIp3PNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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