SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df9bd12e23eaf1cdb66310313dff4a44f138d7f16126bda35fec3b877696cb00' 
  AND token = '7ocGIYW8WT0AXQ9r0E1cwcR9pzcoEKcQO9cqp7b99UY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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