SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c004d57c44473467cb237e0bb92ed7ff6f93f4fdf08d6e0a250f426c884de5b' 
  AND token = 'u/vGATPj9rBXUFFyHkJ5mA0DKcDqd/Wzir4NUw6R6zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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