SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df67ced83a9467c9c52d1756048bf96ffef24bd2632d69219983b8365d301633' 
  AND token = '+owPO/wroQiXbWAUFL0NJOi8JyUDqtalMljVFW9YOL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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