SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c90e0a2e038912ed96f6ce0cbc84d2e9e558951ccec70ae64feac8bac08e25f' 
  AND token = 'mUhWLdBg8fr/zyzZkYeOItYw9YZ+yy7XrYZ7jilXc5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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