SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f465aaaf57e49ac5a077affc4139541eefd292ddfbc32380f61b53d44ceb89a2' 
  AND token = '/YEn1uCHQm7K3mxE0exVfrEDEgkoVUMfSw/iOn8tVww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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