SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '328b25649a27b026e5b31ad0fc931c91d1e6816274a581eade4387b7489695f9' 
  AND token = 'wJPkZemwFAIL10KO7XTkg1ERwyk+S1pnoXSdeL+NbP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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