SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c897773562797e084f4091d8bbea7d34396e1004a0a2bc5e2eea714384f7e0c' 
  AND token = 'ozvLqth0DWGRNbutB/PZKjWJ0YdAwC1brruHkLbkJsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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