SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '003532459339bb759def3c4eeadd1c9c062decf2691d25b5c35e1e6f527e1683' 
  AND token = 'GmcHM+jNahqZEt8bVW82HMBezBHWe/9bwSxtS49mqEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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