SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1599b2e7dc0c3f8560a2e49cbbe5ce0121fe7cd84bf34cc1f3caa4999941b934' 
  AND token = 'Bst5WFuh/jo1vYw22h/nGgRPl+nV5eIsKDWIemEX+K0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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