SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bf317b8baaae8275859052090cfcab1fc3621ba4866363057c2f636c6d5e8e4' 
  AND token = 'k15YJLn/gw7WxJQYpl/cXlEduGVFnzMb0V6/PdwaPjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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