SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6319f79292c1332f42c392d41dca390506b57cd71df4c4609fd6e08c912227b8' 
  AND token = '/RT6Enpmn0BiDRKtdpF097HAHcuQXf7VKODvbHcX8DM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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