SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72e9d808846a81f854903c77aaaab7a6bfcef5c2620ed1cb2571e96448586772' 
  AND token = 'NURpoydMtny2Yc+Nk7u6ZBCaUvbgFtxDF7mPIIfBuek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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