SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67ee50769243d505ce5794c093e42281e2452182050d770ab21dd6a0d487c37e' 
  AND token = 'Mz6bEI9akh5fWPzq0YvJ0qCECfd6NKsmD+roCQjolnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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