SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90a4af30f9ac4bffc30fe20c4ea874010f49b6d3bc5e2f8d7a80f10472234005' 
  AND token = 'KPOWiN4Qxy4XDt9Z2wfGajH/AiG6Hq/+0/yM3PU3pTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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