SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f9d9ba5bb838e47ffcf921e542e77d174f264b563ebc65d49fc8fcf96490743' 
  AND token = 'VWWsuKAPMAttkEZ3dcFry4kDLIqZsOjh+9YJBwVDBeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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