SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58864eb6c43f7c0bc9ed99a59815559a31abef1fee36eaa90abd19293bae513c' 
  AND token = 'pS2o6I8nfUNO5Vs7oCxNwUD4HcDouuAFQ1ZM52jxVmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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