SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65ddf4535917f66bbfa71b8e29cdf9eb38b26794c3ccbac0f03c528c0849f5e1' 
  AND token = 'czvELMMdorYCnP2mGo8Rj/a4gYylFhQFfuHJJWt7KNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}