SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '211be798fa80cf5c9ec2b08788f224716391042c0e4e05a77fb953c57ce3ba3a' 
  AND token = 'S8g8GYyYEpnWQWRh/JLJsQmmzfjTAkVUMhvI2f70/2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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