SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '592da3ec8708ce73e45d99d675948c1ebeda5f33156730460770ebe44bf108f8' 
  AND token = 'MoPl0IYKwlPo3a4zKVWPTgrXshXfiTAad9+bmyPfBdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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