SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956b6d253990153ac7ffe086801acb5782448b0e04930b8067e8a10dc97bc8c5' 
  AND token = 'U5uDjK+peglMnI6E415gKwrzZ4Z237xclQSxZmA11QA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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