SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f327dc1b7bc912877834ced8198625ccb9df1dd4bb43a476e5d5a06852cbc2d' 
  AND token = 'dAh4/+PF5ULll92F0d7L7jBAQkmzGTjZeiWH5EqkFqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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