SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e6bd2a3c33150877f915101cd0cd4fe424c8872949b573633fb9c64359cfb6f' 
  AND token = 'xDlA1JP8UE39kmbAkPGKrfR1Z5nKVevLUcoXzXCyjwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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