SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0df3e2694e5007bb3444e21fa16effc4898e531e004842ba5e1149b1f1e94dc7' 
  AND token = 'RAY6v4rtVJC1F/cYACPbFdZ8WmmsNWAcaMNOAc892ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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